Stoker firing of fuels



March 22, 1966 N. A. MINER, JR

STOKER FIRING OF FUELS Filed March 15, 1963 2 Sheets-Sheet 1 March 22, 1966 N. A. MINER, JR

STQKER FIRING OF FUELS 2 Sheets-Sheet z Filed March 15 INVENTOR.

United States Patent 3,241,506 STOKER FIRING 0F FUELS Nelson A. Miner, Jr., Kerr County, Tex. (P.O. Box 558, Comfort, Tex.) Filed Mar. 15, 1963, Ser. No. 265,465 1 Claim. (Cl. 110--105.5)

This invention relates to improvements in the stoker firing of fuel in furnaces such as are associated with boilers, incinerators, smelters, kilns, ovens and the like and in accordance with the present invention improved means is provided for evenly distributing the fuel in the furnace and also improved means is provided for adding a fluid (hereinafter called air) both to assist in the distribution of fuel and to assist in good combustion of the combustible gases above the fuel bed by being secondary combustion air as well as air which will provide turbulence, thereby assisting combustion by helping to intimately mix the combustion gases with air, thus resulting in improved combustion and a reduction in smoking of the furnace.

The invention together with its numerous objects and advantages will be best understood from a study of the following description taken in connection with the accompanying drawings which illustrate one form of the invention.

In the accompanying drawings,

FIG. 1 represents a diagrammatic longitudinal, vertical section through a furnace showing my improved spreader stoker mechanism as it would be installed in order that it could spread the particles of fuel, which it would receive from a feeder mechanism shown above, on to the grates shown in the furnace.

FIG. 2 is a sectional, elevational view of my new spreader stoker mechanism enlarged in size so as to more clearly show its parts and their relation to each other.

FIG. 3 is a plan view showing three and a portion of a fourth of my new fuel spreader or injector mechanisms and an arrangement of a number of these injectors installed in the same furnace. In the interest of clarity the throat 102 portions are deleted from this view. In actual practice a throat 102 would be installed in each of the openings shown in the refractory 101.

FIG. 4 represents a longitudinal, sectional view as it would appear when out by a plane passing through or near the centers of the air supply duct 142 and the deflector plate/nozzle/air tube assembly 110, 111, 109. This view also has the throat 102 portions deleted in the interest of clarity.

Now referring to the drawings 101 indicates the heat resistant walls of this furnace; 103 indicates the grate structure which receives and supports the heavier particles of fuel during combustion. Air openings are provided in this grate structure and a portion of the combustion air required is supplied through the air plenum and ash pit 104; through a controllable damper 105;, either from the surrounding atmosphere as natural draft or as forced draft; in this drawing I have symbolized as 150 as forced draft fan driven by a constant speed motor. Fuel for my stoker would normally be received and temporarily stored in a receptacle or bin shown as 106 from which it is discharged as needed by a controllable feeding or metering device shown in this drawing as a feed screw 107 (this shown as being driven by a variable speed motor 140) down through a chute or duct 108 for injection or spreading into the previously described furnace by my improved spreader stoker Inechanism. The improved method of distributing fuel hereinafter described and particularly pointed out in the claims and accompanying drawings results from the use of a constantly oscillating deflector plate/nozzle/air tube assembly 110, 111, 109. Referring again to FIG. 1 of 'ice the drawings, as the fuel slides down the chute or duct 108 and into the throat 102 of this stoker, it will be deflected and directed into the furnace by a deflector plate 110 and also by a controlled jet of fluid (hereinafter called air) issuing from a properly designed nozzle 111. One method, but not necessarily the only method, of arranging for the proper oscillation of the nozzle 111 and deflector plate 110 would be to firmly fix this nozzle 111 and deflector plate 110 to an air supply tube or plenum 109 so that said tube 109 could then serve as both a supply duct and also as a supporting member. In this case it would be advantageous to so construct and arrange this deflector plate/nozzle/tube assembly 110, 111, 109 in order that it would be capable of being supported in pivots or bearings in order that it could move in an oscillating motion all the while it is receiving its air supply. This deflector plate/:nozzle/tube assembly 110, 111, 109 would then be located in close proximity to two edges 112 and 113 which are prepared in the stoker throat 102 portion; this top edge 112 and the bottom edge 113 would thus act as a seal along the longitudinal portion of the tube 109. The two ends or sides of throat 102 would be closed and also arranged to fit in close proximity to tube 109' as well as having suflicient clearance to allow the ends of the nozzle 111 and deflector plate 110 to operate freely. This all being so arranged that this deflector plate/nozzle/ tube assembly 110, 111, 109 could then be continually oscillated through an are all without undue friction of interference between the deflector plate/nozzle/tube assembly 110, 111, 109 and the top and bottom edges 112 and 113, and the two ends or sides of the throat. All this being so arranged that there will be a minimum of leakage, either of outside air into the furnace or of furnace gases leaking out of the furnace into the sur rounding atmosphere. One method of arranging for a continuous supply of air to the nozzle and also of supporting this deflector plate/nozzle/tube assembly 110, 111, 109 so that it might oscillate as a unit would be to furnish the ends of this tube so that it could be supported at each end and 126 (reference FIG. 4) by stationary bearings 127 and 128. These bearings could then be fastened to stationary windboxes or plenums 129 and 130 which could be supplied with dampers 131 and 132 to adjust, control, and if necessary close off the quantity and/or pressure of the nozzle air supply. These windboxes would be arranged so as to receive their supply of air from the supply duct 142 through distributing ducts 143.

A mechanism for oscillating this deflector plate/nozzle/tube assembly 110, 111, 109 is also provided so that this assembly can be continuously oscillated through an arc of several degrees all the while with the nozzle being furnished its required supply of air. The oscillating mechanism is made so as to be adjustable as to the portion of the are this assembly will oscillate in and also variable or adjustable in the amount of are or number of degrees that it will oscillate. This means that it can 'be adjusted so that the deflector plate/nozzle/tube assembly 110, 111, 109 can continually oscillate while pointing to a relatively high position, to an infinite number of intermediate positions, or also, of course, to a relatively low position. The are or degree of oscillation is also made adjustable through as wide a range as may be required. One method of doing this is shown (reference FIG. 2) with 114 representing a crank disk, 115 the connecting: rod, 116 the connecting rod adjusting device so arranged that the length of this connecting rod 115 may be changed at will; 117 represents an arm aflixed to the deflector plate/nozzle/ tube assembly 110, 11.1, 109 so that with the crank disk 114 rotating about its center of rotation 141 and with the connecting rod 115 then moving back and forth that the deflector plate/nozzle/tube assembly 110, 1111, 109 will of necessity then oscillate about its center of rotation 140. The crank disk 114 may be driven by a variable speed device such as a variable speed motor, engine or some other adjustable speed driving mechanism; this is shown in FIG. 4 as a variable speed motor 145. The connecting rod length adjusting mechanism 116 is provided so that the length of the connecting rod between crank pin 121 in the crank disk and crank pin 122 in arm 117 may be adjusted as desired; this in order that the relative position of the deflector plate/nozzle/tube assembly 110, 111, 109 may be changed so that this deflector plate/ nozzle/tube assembly 110, 111, 109 can be made to point to a relatively high position, to an infinite number of intermediate positions or, of course, to a relatively low position while it oscillates. The are or degree of oscillation of this deflector plate/nozzle/tube assembly 10, 1'11, 109 is also to be made adjustable as required through as wide a range as may be necessary; one, but not necessarily the only method, being by providing as many holes as might be desired at different radii from the center of rotation 141 in the crank disk 114. With this crank disk 114 so arranged with these several holes, some shown in FIG. 2 as 118, 1 19 and 120 and with these holes at various radii from the rotation center 1411 of the crank disk i114 and so arranged that crank pin 1 21 may be positioned and properly fastened in either of these several holes, then this travel of the connecting rod 115 and arm 1-17 may be increased or decreased as desired in order that the amount of angular oscillation of the deflector plate/nozzle/tube assembly 110, 111, 109 may be adjusted as desired.

By providing this continually oscillating deflector plate 110 my invention will improve the distribution of fuel in the furnace because the particles of fuel moving down chute 8 and on into the furnace through throat 102 will be deflected different distances when this deflector plate is in its different positions or angles. When the angle of oscillation of the deflector plate 110 and also its relative position while oscillating are correctly adjusted, fuel can be more accurately and uniformly distributed over the Whole of the fuel bed than with a nonoscillatory deflector plate.

While the changing of its angle or position by continually oscillating the deflector plate 110 improves the distribution of the fuel, still further improvement is made by the spreading effect of the constantly moving jet of air issuing from the oscillating air nozzle 111. With the deflector plate 110 and the air nozzle 11'1 continually oscillating through their adjusted angle, fuel received down chute 108 can be very evenly spread from the front of the grate (near the stoker mechanism) to the back of the grate. This is a benefit to the user since it is a well established fact that optimum efliciencies and rates of combustion accrue when a fuel bed is evenly distributed. There are other benefits as a result of the oscillating jet of air issuing from nozzle 111. The use of secondary combustion air blown into the furnace through nozzles into the combustible gases above the fuel bed is a presently known art, but my invention of oscillating the nozzle or nozzles used for the introduction of secondary combustion air is new, and its use results in a marked improvement in furnace efficiency due to the resulting increase in turbulence and the better mixing of these combustible gases and air that then occurs. This improves combustion thus resulting in higher efliciency and less smoke emission from furnaces thusly equipped.

I recognize that prior to my invention spreader stoker machines have been made both with adjustable deflector plates and with air nozzles to assist in the distribution of fuel. 1 also recognize the fact that air nozzles have been employed to introduce secondary combustion air into furnaces and to give turbulence to the combustion gases. I therefore do not claim such a combination broadly; but I claim:

In a furnace, apparatus for distributing fuel in a furnace, improving furnace turbulence and providing air needed for the secondary combustion of gases within said furnace comprising a chute connected to said furnace, a horizontally extending slot in the rear wall of said chute, a rotatable horizontal tubular member secured to said chute, a deflector plate secured to said tubular member, said plate passing through said slot and terminating in said chute toward said furnace to receive and support 'fuel particles deposited thereon, means to provide oscillation of said tubular member about its axis, nozzle means connected to said tubular member, said nozzle means passing through said slot and terminating in said chute, a source of air connected to said nozzle means, said nozzle means cooperating with said deflector plate whereby said air assists in the distribution of the fuel deposited upon said deflector plate and causes turbulence and provides for the secondary combustion of gases within the furnace.

References Cited by the Examiner UNITED STATES PATENTS 2,130,329 5/1935 Sammons 113 2,155,608 7/1936 Lippert 110105.5 2,359,887 5/ 1942 Barr 11.0--105.5 2,654,331 5/1950 Mosshart 110-413 FREDERICK L. MATTESON, JR., Primary Examiner.

JOHN J. CAMBY, JAMES W. WESTHAVER,

Examiners.

D. A. TAMBURRO, Assistant Examiner. 

